Private Equity: An Emerging Practice Model.

Private equity acquisitions are increasing among orthopedic practices. The concepts and vocabulary surrounding these deals may be foreign to physicians. There are both potential risks and potential benefits to physicians at the center of these complex deals, and a clear understanding of any proposed private equity acquisition is crucial. Short-term data on private equity acquisition in other procedure-based outpatient specialties have shown that private equity ownership consistently increased the number of patients seen per provider, allowed amount per claim, and utilization of advanced practice practitioners. These studies did not show consistent changes in the rates of invasive procedures or negative impacts on patient care. Each practice will need to carefully consider any potential private equity involvements.

Ligamentous hyperlaxity and dorsal wrist ganglions.

PURPOSE: To determine whether symptomatic dorsal wrist ganglions are associated with generalized ligamentous hyperlaxity. METHODS: Ninety-six patients (61 females) presenting to hand surgeons for a symptomatic dorsal wrist ganglions were prospectively enrolled in this case-control investigation. Beighton scores were calculated to quantify generalized ligamentous laxity in each patient, and a scaphoid shift test (scapholunate capsuloligamentous laxity evaluation) was performed. A positive scaphoid shift test was defined by both pain and a palpable clunk. Ninety-six individuals without ganglions were then enrolled to form an age and sex frequency-matched control cohort. The control group was similarly assessed for Beighton score and scaphoid shift test. Binary logistical regression was performed to assess the association of ganglions with generalized ligamentous hyperlaxity (Beighton score ≥ 4) while accounting for effects of age and sex. RESULTS: Patients with symptomatic dorsal wrist ganglions demonstrated significantly increased rates of generalized ligamentous hyperlaxity. Among those with ganglions, 27 of 96 (28%) patients exhibited generalized ligamentous hyperlaxity, compared with 12 of the 96 (13%) age- and sex-matched individuals in the control group. Patients with symptomatic dorsal wrist ganglions were also significantly more likely to demonstrate localized scapholunate hyperlaxity with a positive scaphoid shift test (25% positive scaphoid shift test with ganglions vs 1% in controls). In logistical modeling, patients with dorsal wrist ganglions had 2.9 (95% confidence interval [CI] 1.3-6.2) times greater odds of generalized ligamentous hyperlaxity compared with patients without a dorsal wrist ganglion after accounting for patient age and sex. CONCLUSIONS: Symptomatic dorsal wrist ganglions were associated with both generalized ligamentous hyperlaxity and a positive scaphoid shift test. Although an association between wrist ganglions and ligamentous hyperlaxity does not prove causation, the possibility of the same underlying pathological entity causing both can be envisioned (ie, abnormal formation or organization of dense regular connective tissue). TYPE OF STUDY/LEVEL OF EVIDENCE: Prognostic III.

The intraosseous and extraosseous vascular supply of the fifth metatarsal: implications for fifth metatarsal osteotomy.

BACKGROUND: Osteotomies of the fifth metatarsal may disrupt the nutrient artery and result in nonunion. The location of the nutrient artery foramen relative to the location of common osteotomies has not been described. The goal of this study was to describe the vascular supply of the proximal fifth metatarsal, including the artery of origin of the nutrient artery and the location of the nutrient artery foramen. METHODS: Fifty-six adult cadaver specimens were amputated below the knee. The anterior tibial, posterior tibial, and peroneal arteries were injected with India ink and Ward's Blue Latex. The specimens were frozen for 48 hours and then thawed to room temperature. The soft tissues were débrided with sodium hypochlorite, and the extraosseous vascularity was recorded. The fifth metatarsal was then removed and the intraosseous vascular anatomy elucidated using a modified Spälteholz technique. RESULTS: The dorsalis pedis, posterior tibial, and peroneal arteries branch in predictable patterns to supply the fifth metatarsal. The nutrient artery arose from the fourth plantar metatarsal artery in 100% of specimens and inserted into the plantar medial diaphysis in 83% of specimens. The nutrient artery foramen was an average of 26.8 mm (range, 19-40) from the medial aspect of the base of the fifth metatarsal. CONCLUSIONS: When an operative approach to the fifth metatarsal is planned, care should be taken to avoid stripping the bone on the plantar and medial aspects. CLINICAL RELEVANCE: Osteotomies placed within the proximal 40 mm of the bone carry a risk of disrupting the nutrient artery, resulting in possible nonunion.

Stress fracture of the radius diaphysis in a skeletally immature wrestler.

Stress fractures in the forearm are rare events. Failure to detect a nondisplaced stress fracture could lead to further injury or fracture displacement. We present a case of a 15-year-old male wrestler without overt risk factors, who presented with a transverse stress fracture in the middle third of the radial diaphysis. The clinician should consider this diagnosis when examining athletes with otherwise unexplained forearm pain.

Immobilization after pinning of supracondylar distal humerus fractures in children: use of the A-frame cast.

BACKGROUND: Circumferential casts can contribute to elevated compartment pressures in the setting of acute swelling. We have developed a novel casting method (A-frame cast) that allows cast placement while leaving the antecubital fossa free of casting material. The purpose of this study was to evaluate the safety, efficacy, and complications associated with acute placement of this definitive cast after closed reduction percutaneous pinning (CRPP) of acute supracondylar distal humerus fractures. METHODS: A retrospective medical record reviewed 436 patients treated with CRPP of supracondylar fractures by 3 surgeons who routinely used an A-frame cast over a 12-year period. All complications or the need for cast modification were noted. Patients with open reduction, ipsilateral fractures, or patients lost to follow-up were excluded. RESULTS: There were 387 patients who met inclusion criteria, including 204 type 2 fractures and 183 type 3 fractures. Forty-three patients had preoperative nerve palsy and 1 had preoperative vascular injury. Of these 387 patients, 369 (95.3%) had an uneventful postoperative course. Nineteen patients (4.9%) required either cast splitting (15) or strict elevation (4) secondary to pain and swelling. Seven of these 19 patients had preoperative nerve palsy and 1 had preoperative vascular injury. The average time from procedure to cast splitting was 17.6 hours. No patients lost their reduction or required a second surgical procedure related to a complication from casting. CONCLUSIONS: An "A-frame" cast provides sturdy immobilization without increased risk of compartment syndrome after CRPP of supracondylar fractures in the pediatric population. Consideration should be given to splitting the cast prophylactically in patients with preoperative neurological or vascular deficits. LEVEL OF EVIDENCE: IV-Case Series.

Intraosseous and extraosseous arterial anatomy of the adult navicular.

BACKGROUND: The etiology of navicular stress fractures is a topic of interest due to the implications in high-level athletes. Previous studies suggest an avascular zone in the central one-third of the bone as a potential causative factor. This study investigated the extraosseous and intraosseous arterial anatomy of the adult navicular. METHODS: Sixty legs from 30 cadavers were amputated below the knee. India Ink and Wards Blue Latex were injected into the anterior tibial, peroneal, and posterior tibial arteries. The specimens were frozen, thawed to room temperature, and the skin was sharply dissected away. The soft tissues were chemically debrided, leaving the bones, interosseous ligaments, and casts of the extraosseous blood vessels. The vascular supply to the navicular was elucidated in 55 specimens. The navicular was then cleared using a modified Spälteholz technique; the intraosseous vascularity was reviewed in 54 specimens. RESULTS: Medial tarsal branches of the dorsalis pedis consistently supplied the dorsal navicular (96.4%). Lateral tarsal branches of varying size and distribution patterns also supplied the dorsal navicular. The medial plantar bone received small branches from the superficial branch of the medial plantar artery. Thirty of 54 specimens had a diffuse intraosseous vascular supply throughout the bone. Only six (11.8%) specimens had an avascular zone in the central third of the navicular extending to the dorsal cortex. CONCLUSION: The dorsalis pedis and posterior tibial arteries branch to supply blood flow to the navicular. In the majority of these specimens the navicular had a dense intraosseous vascular supply throughout it. CLINICAL RELEVANCE: If diminished vascular supply is a contributing factor to navicular stress fracture, our results suggest that a relatively small proportion of individuals is prone to their development. Biomechanical or other clinical factors may play a more prominent role in the development of navicular stress fractures than previously suspected.

Arterial Anatomy of the Posterior Tibial Nerve in the Tarsal Tunnel.

BACKGROUND: Both vascular and compression etiologies have been proposed as the source of neurologic symptoms in tarsal tunnel syndrome. Advancing the understanding of the arterial anatomy supplying the posterior tibial nerve (PTN) and its branches may provide insight into the cause of tarsal tunnel symptoms. The purpose of this study was to describe the arterial anatomy of the PTN and its branches. METHODS: Sixty adult cadaveric lower extremities (thirty previously frozen and thirty fresh specimens) were amputated distal to the knee. The vascular supply to the PTN and its branches was identified, measured, and described macroscopically (the thirty previously frozen specimens, prepared using a formerly described debridement technique) and microscopically (the thirty fresh specimens, processed using the Spälteholz technique). RESULTS: On both macroscopic and microscopic evaluation, the PTN and the medial and lateral plantar nerves were observed to have multiple entering vessels within the tarsal tunnel. On microscopic evaluation, a vessel was observed to enter the nerve at the bifurcation of the PTN into the medial and lateral plantar nerves in twenty-two (73%) of the thirty specimens. There was a significant difference (p < 0.05) in vascular density between the PTN and each of its branches. CONCLUSIONS: The abundant blood supply to the PTN and its branches identified in this study is consistent with observations of other peripheral nerves. This rich vascular network may render the PTN and its branches susceptible to nerve compression related to vascular congestion. The combination of vascular and structural compression may also elicit neurologic symptoms. CLINICAL RELEVANCE: Advancing the understanding of the arterial anatomy supplying the PTN and its branches may provide insight into the cause and treatment of tarsal tunnel syndrome.

Posttraumatic Boutonnière and Swan Neck Deformities.

Boutonnière and swan neck deformities of the finger can be the result of trauma. The complex anatomy of the extensor mechanism of the finger makes understanding the pathomechanics of these deformities challenging. These posttraumatic deformities should not be confused with those associated with inflammatory arthritis because the treatment options are often very different. An accurate clinical assessment is essential for selecting the appropriate treatment method. Physical examination, including Elson and intrinsic-plus tests, and plain radiography are important tools for diagnosis. A variety of nonsurgical and surgical treatment modalities can be used to restore the motion of the proximal and distal interphalangeal joints and rebalance the forces across these joints. An understanding of the anatomy, clinical presentation, treatment options, and expected outcomes is crucial for optimal treatment of posttraumatic boutonnière and swan neck deformities.

Accuracy of MRI-based Diagnoses for Distal Upper Extremity Soft Tissue Masses.

UNLABELLED: To determine the accuracy of the pre-operative MRI-based diagnosis of soft tissue masses in the forearm, wrist, and hand, the records of 144 patients who underwent an MRI followed by excision of a soft tissue mass in the forearm, wrist, or hand were reviewed. The MRI-based diagnosis was compared to the histological diagnosis, which was considered the gold standard. The sensitivity, specificity, positive predictive value, and negative predictive value of the MRI-based diagnosis were calculated. A multivariate regression analysis was performed.While the accuracy of the MRI-based diagnosis varied widely, there was an overall sensitivity of 75 %. The most accurate diagnosis was an MRI-based diagnosis of ganglion cyst, which had a sensitivity of 94.7 % and a specificity of 94.4 %. Of particular concern was that the MRI-based diagnosis of a malignancy was only 66.7 % sensitive, with a positive predictive value of 44.4 %. On multivariate regression analysis, there was a trend towards improved accuracy in the wrist when compared to the finger, although this did not reach statistical significance.While pre-operative MRI remains a valuable tool for the evaluation of soft tissue masses in the distal upper extremity, caution is warranted when basing the diagnosis on MRI evidence alone. LEVEL OF EVIDENCE: Level IV/Diagnostic.

Arterial anatomy of the tibialis posterior tendon.

BACKGROUND: Tibialis posterior tendon dysfunction is a common disorder leading to pain, deformity, and disability, although its pathogenesis is unclear. A vascular etiology has been proposed, but there is controversy regarding the existence of a hypovascular region that may render the tendon vulnerable. The purpose of this study was to provide a description of the arterial anatomy supplying the tibialis posterior tendon. METHODS: Sixty adult cadaveric lower extremities were obtained from a university-affiliated body donation program. Thirty specimens obtained within 72 hours of death were used for microscopic analysis. Thirty specimens were previously frozen and used for macroscopic analysis. The tibialis anterior, tibialis posterior, and peroneal arteries were injected with India Ink and Ward's Blue Latex. The specimens used for macroscopic analysis were debrided with sodium hypochlorite to expose the extratendinous anatomy. For the microscopic analysis, the tendon was cleared using a modified Spälteholz technique to expose the intratendinous vascular anatomy. RESULTS: Macroscopically, an average of 2.5 ± 0.7 vessels entered the tendon proximal to the navicular insertion. In all, 28/30 (93.3%) specimens had a vessel entering 4.1 ± 0.6 cm proximal to the medial malleolus and 24/30 (80.0%) specimens had a vessel entering 1.7 ± 0.9 cm distal to the medial malleolus. Microscopically, an average of 1.9 ± 0.3 vessels entered each tendon proximal to the navicular insertion. In total, 27/30 (90%) specimens had a vessel entering the tendon 4.8 ± 0.8 cm proximal to the medial malleolus and 30/30 (100%) specimens had a vessel entering the tendon 1.9 ± 0.8 cm distal to the medial malleolus. In all specimens, a hypovascular region was observed, starting 2.2 ± 0.8 cm proximal to the medial malleolus and ending 0.6 ± 0.6 cm proximal to the medial malleolus with an average length of 1.5 ± 1.0 cm. The insertion of the tendon was well vascularized both on microscopic and macroscopic specimens. CONCLUSION: The tibialis posterior tendon was supplied by 2 vessels entering the tendon approximately 4.5 cm proximal and 2.0 cm distal to the medial malleolus. A retromalleolar hypovascular region was observed. CLINICAL RELEVANCE: Improved understanding of the vascularity of the tibialis posterior tendon may be helpful in clinical practice and potentially provides a basis for further evaluation of the causative factors of tibialis posterior tendinopathy.

Intraosseous and extraosseous blood supply to the medial cuneiform: implications for dorsal opening wedge plantarflexion osteotomy.

BACKGROUND: Osteotomies of the medial cuneiform are commonly used to correct forefoot deformity. Bone healing occurs despite periosteal stripping of the dorsal and medial surfaces of this widely articulated bone followed by osteotomy in the midsection of the bone. The objective of this study was to characterize the blood supply of the medial cuneiform. METHODS: Thirty matched pairs of adult cadaver legs, 60 legs total, were amputated below the knee, and arterial casts were created with India ink and latex. Soft tissues were debrided, allowing visualization of the extraosseous blood vessels. In 53 specimens the vascular supply to the medial cuneiform was photographed and recorded. Forty-nine specimens were then cleared using a modified Spälteholz technique. The intraosseous vascularity of the medial cuneiform was successfully characterized and reviewed in 48 of these specimens. RESULTS: The extraosseous blood supply was similar to previous reports with a middle pedicle branch originating from the dorsalis pedis artery. The medial plantar and superficial medial plantar artery supplied the plantar aspect of the bone. Intraosseous analysis showed a dense capillary network throughout the cuneiform, with typically one central medial major and several minor nutrient arteries noted. Areas of hypovascularity were infrequent and when noted occurred at inconsistent locations. CONCLUSION: These findings support the clinical suspicion that the medial cuneiform is well vascularized from multiple sources. The plantar blood supply is likely sufficient to allow bone healing after dorsal periosteal exposure and possible injury to the middle pedicle branch of the distal medial tarsal artery. CLINICAL RELEVANCE: A medial cuneiform opening wedge osteotomy can be used to correct forefoot deformity. This study investigates the blood supply to that bone to better characterize the healing potential of the medial cuneiform.

Ulnar collateral ligament injuries of the thumb: phalangeal translation during valgus stress in human cadavera.

BACKGROUND: The clinical diagnosis of thumb ulnar collateral ligament disruption has been based on joint angulation during valgus stress testing. This report describes a definitive method of distinguishing between complete and partial ulnar collateral ligament injuries by quantifying translation of the proximal phalanx on the metacarpal head during valgus stress testing. METHODS: Sixty-two cadaveric thumbs underwent standardized valgus stress testing under fluoroscopy with the ulnar collateral ligament intact, following an isolated release of the proper ulnar collateral ligament, and following a combined release of both the proper and the accessory ulnar collateral ligament (complete ulnar collateral ligament release). Following complete ulnar collateral ligament release, the final thirty-seven thumbs were also analyzed after the application of a valgus force sufficient to cause 45° of valgus angulation at the metacarpophalangeal joint to model more severe soft-tissue injury. Two independent reviewers measured coronal plane joint angulation (in degrees), ulnar joint line gap formation (in millimeters), and radial translation of the proximal phalanx on the metacarpal head (in millimeters) on digital fluoroscopic images that had been randomized. RESULTS: Coronal angulation across the stressed metacarpophalangeal joint progressively increased through the stages of the testing protocol: ulnar collateral ligament intact (average [and standard deviation], 20° ± 8.1°), release of the proper ulnar collateral ligament (average, 23° ± 8.3°), and complete ulnar collateral ligament release (average, 30° ± 8.9°) (p < 0.01 for each comparison). Similarly, gap formation increased from the measurement in the intact state (5.1 ± 1.3 mm), to that following proper ulnar collateral ligament release (5.7 ± 1.5 mm), to that following complete ulnar collateral ligament release (7.2 ± 1.5 mm) (p < 0.01 for each comparison). Radial translation of the proximal phalanx on the metacarpal head did not increase after isolated release of the proper ulnar collateral ligament (1.6 ± 0.8 mm vs. 1.5 ± 0.9 mm in the intact state). There was a significant increase in translation following release of the complete ulnar collateral ligament complex (3.0 ± 0.9 mm; p < 0.01) and an additional increase after forcible angulation of the joint to 45° (4.1 ± 0.9 mm; p < 0.01). Translation 2 mm greater than that in the stressed control was 100% specific for complete disruption of the ulnar collateral ligament complex. CONCLUSIONS: While transection of the proper ulnar collateral ligament leads to an increase in metacarpophalangeal joint angulation and gapping on stress fluoroscopic evaluation, only release of both the accessory and the proper ulnar collateral ligament significantly increases translation of the proximal phalanx on the metacarpal head.

Vascular anatomy of the tibiofibular syndesmosis.

BACKGROUND: Injuries to the tibiofibular syndesmosis commonly cause prolonged ankle pain and disability. Syndesmotic injuries are associated with slower healing rates compared with rates for other ankle ligament injuries and typically result in longer time away from sports. To our knowledge, the vascular supply to the syndesmosis and its clinical implication have not previously been studied. The purpose of this study was to describe the vascular supply to the tibiofibular syndesmosis with use of a method of chemical debridement of cadaveric specimens. METHODS: Twenty-five matched pairs of adult cadaver legs, fifty legs total, were amputated below the knee. India ink, followed by Ward Blue Latex, was injected into the anterior tibial, peroneal, and posterior tibial arteries under constant manual pressure to elucidate the vascular supply of the ankle syndesmotic ligaments. Chemical debridement was performed with 6.0% sodium hypochlorite to remove soft tissue, leaving bones, ligaments, and casts of the vascular anatomy intact. The vascular supply to the syndesmosis was evaluated and recorded. RESULTS: The anterior vascularity of the syndesmosis was clearly visualized in forty-three of fifty specimens. The peroneal artery supplied an anterior branch (the perforating branch) that perforated the interosseous membrane, an average of 3 cm proximal to the ankle joint. This branch provided the primary vascular supply to the anterior ligaments in twenty-seven specimens (63%). The anterior tibial artery provided additional contribution to the anterior ligaments in the remaining sixteen specimens (37%). CONCLUSIONS: The location of the perforating branch of the peroneal artery places it at risk when injury to the syndesmosis extends to the interosseous membrane 3 cm proximal to the ankle joint. In the majority of specimens, injury to this vessel would result in loss of the primary blood supply to the anterior ligaments.